William J. Macquorn Rankine, the Scotch engineer and philosopher, will always be remembered as the author of the modern philosophy of the steam-engine, and as the greatest among the founders of the science of thermo-dynamics. His death, while still occupying the chair of engineering at the University of Glasgow, December 24, 1872, at the early age of fifty-two, was one of the greatest losses to science and to the profession which have occurred during the century.
[103] Their estimate of the length of the Saros, or cycle of eclipses—over 19 years—was “within 191∕2 minutes of the truth.”—Draper.
[104] “History of Civilization in England,” vol. i., p. 208. London, 1868.
[105] “Philosophical Transactions,” 1798.
[106] This idea was not by any means original with Rumford. Bacon seems to have had the same idea; and Locke says, explicitly enough: “Heat is a very brisk agitation of the insensible parts of the object ... so that what in our sensation is heat, in the object is nothing but motion.”
[107] The British heat-unit is the quantity of heat required to heat one pound of water 1° Fahr. from the temperature of maximum density.
[108] Rankine gives 25,920 foot-pounds per minute—or 432 per second—for the average draught-horse in Great Britain, which is probably too high for Bavaria. The engineer’s “horse-power”—33,000 foot-pounds per minute—is far in excess of the average power of even a good draught-horse, which latter is sometimes taken as two-thirds the former.
[109] Vide Tait’s admirable “Sketch of Thermodynamics,” second edition, Edinburgh, 1877.
[110] “New Experiments, Physico-Mechanical, etc., touching the Spring of Air,” 1662.